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Revy-Saerang-Analytical- Problem- Titanium Dioxide in Masterbatch

Titanium Dioxide is a natural chemical that is used extensively in agriculture, cosmetic, food and coloring industry. Titanium dioxide, when used in colored industry, is an inorganic white pigment that is largely consumed in the coloring industry to enhance the opactiy, the whiteness and to achieve a desirable visual impact.(2)

The special chemical and physical features of Titanium dioxide as an inorganic white pigment are incorporated with other ingredients such as additives, colored pigments and resins in colored masterbatch production (masterbatch is a high concentrated pigment carrier for food & beverage packaging, cosmetic packaging, computer hardware production, etc) production. (1)

My interest is to recognize the nature of titanium dioxide in causing the coloration on color pigmented carrier (masterbatch) for plastic to be non-reproducible for one production to the next. When this happened, the quality control lab has to reformulate a more stable formula and remixing product has to be done.Reformulation is ideally to be avoided because it increases the capital cost of production for each batch and it influences customers' satisfaction on products made by the company. Through analytically studying the effect of titanium Dioxide in masterbatch, a method of study or a new technique could be devised and implemented to improve the production process of both white and colored masterbatches.(3)

My hypothesis is that titanium dioxide being larger in particle in comparison to other components in masterbatch formulation has lead to non-homogeneity of mixing and to cause a hindrace of pigment dyability in colored masterbatch production during coloration and pigmentation.

The analyte that I will focus on is Titanium Dioxide and it could be found in the mixture components of polymer resin, additives (antioxidants, Silicon oxide) and other inorganic pigments.


UV-Vis absorption spectrometry
The range of wavelength of titanium dioxide can be related closely to the preparation method of titanium oxide itself. For titanium dioxide with a commercial name Degussa P25 titanium dioxide (consists of 80% anatase and 20% rutile) that have been chemically treated with polymer compositions, it is found that the wavelengths of absorption for my analytes ranges from 400 to 600 nm. It is important to consider that this absorption spectra may be differed if some methods are not implemented when measurements are made such as the analyte has to subjected to low-temperature heat treatment above 350 K and making BaSO4 as a reference standard to the spectometer. (4)

Unfortunately, I could not find an optical density of my analyte within the wavelength range that I found from 400 to 600 nm. However, I found in source (5) that at wavelength 310 nm, titanium dioxide has an optical density of 0.8785. This data was found from a research paper that focused its interest of particle size measurement of titanium dioxide in safety of efficacy of nanotechnology.

In doing a research about UV-Vis absorption spectroscopy, I learnt that it will be a brilliant idea to narrow down my analytical problem to a particular method. So while finding more resources and getting more information from the class, I will attempt to assume that my analyte is prepared similarly with source (4).

Similiar Analytical Problem(s)
a)
Exposure to Zinc Oxide and Titanium Dioxide Nanoparticles in Sunscreen by Heidi Nelson Heidi talks aboout the commercial uses of nanoparticles in sunscreen and its impact on human health and the environment. Her central hypothesis is to determine whether or not nanoparticles could be detected in blood or only present at the top layer of the skin after sunscreen's application on human's skin. The analytes for her analytical problem will be both zinc oxide and titanium dioxide nanoparticles and the matrix will be human skin and body. Other than the fact that we both focus on similiar analyte, I think my analytical problem mainly focus on particle size of the analyte and the optical properties that it has such as scattering of light, dispersion, etc.

b)
For both our analytical problems, the optical properties of nanoparticles relate closely with a particle size and distribution, it is important to separate these nanoparticles by size and then measure the concentration according to the signal response making use of calibration curves. With these measurements, multiple sampling will help me to calculate and analyze the particle size distribution and how the content of TiO2 as our analytes. For my anaytical problem, I could analyze the deviation of other pigments and additives to mix homogenously and reproduce similar masterbatch production with both standard or previous masterbatch production.

c)
In comparing the differences of studies between my analytical problem and Heidi's, it is important to recognize the matrix which in Heidi's case will be the human skin and the blood where in my case will be polymer resin or other pigments. With this being said, I think Heidi has to do separation before collecting the UV-vis spectra because she is dealing with analyte in more delicate yet complex matrix system. As for me, I will separate my analyte using a normal chromatography method to separate the nanoparticles and get a number to find the nanoparticle concentration later by using UV-vis.

References:
Ahmed, S. I., Shamey, R., Christie, R. M. and Mather, R. R. (2006), Comparison of the performance of selected powder and masterbatch pigments on mechanical properties of mass coloured polypropylene filaments. Coloration Technology, 122: 282-288. doi: 10.1111/j.1478-4408.2006.00042.x (1)

Fisher, J. and Egerton, T. A. 2001. Titanium Compounds, Inorganic. Kirk-Othmer Encyclopedia of Chemical Technology.(2)

Russell, S. (2005) Color Compounding, in Coloring of Plastics: Fundamentals (ed R. A. Charvat), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/0471721581.ch18(3)

Vyacheslav, N. and Serpone, N. (2006) Visible Light Absorption by Various Titanium Dioxide Specimens, American Chemical Society. Russia. doi:25203 (4)

Delrieu, P. Particle Size Measurement of Attenuation Grade Titanium Dioxide in Diespersion and Sunscreen Lotion, Kobo products(5)

Blog 6- Chemical Structure and Standards

2. The chemical structure of my analyte, Titanium Dioxide (rutile form) is:
View image

Reference:
http://rruff.geo.arizona.edu/xtal/group/pdf/am88_247.pdf
(accessed on October 24, 2011)

3. Information about my standards:
Company name: DuPont
Catalogue number: DuPont R-104 titanium dioxide
Quantity: 25 kg (packaged in polyethylene bag)
Price: Not available online (Need to contact local agent)

Reference:
http://www2.dupont.com/Titanium_Technologies/en_US/products/104/R104_Intro_Brochure.pdf
(accessed on October 24, 2011)

Blog 7- Atomic and Mass Spectrometries
The analyte that I will be looking for spectrometries will be Titanium dioxide. I think atomic spectrometries can be used to quantify the analyte of my analytical problem, however considering the preparation of analysis and a method to convert solid sample into solution suitable for analysis could be very time-consumptive and it also limits to eliminate the particle size effect application of titanium dioxide. Based on one study I found, ICP-OES/MS can be employed using slurry nebulization and electrothermal vaporization to deal with solid sample, therefore this will be desirable for my analytical problem in excluding out all the impurities before quantifying the concentration of titanium dioxide.

Reference:
JOURNAL OF MASS SPECTROMETRY
J. Mass Spectrom. 2006; 41: 1378-1385
Published online 29 September 2006 in Wiley InterScience
(www.interscience.wiley.com) DOI: 10.1002/jms.1111

Blog 11. Capillary Electrophoresis Techniques

1. Capillary Zone electrophoresis is only good to separate ionic species based on their charge, where MEKC (Micellar Electrokinetic Chromatography) is mostly used to separate DNA and proteins (or biomolecular compounds). Capillary Isoelectric Focusing Electrophoresis) is done based on the isoelectric measure or pH of the analyte. Due to this reasoning, the best separation technique of CE would be CGE (Capillary Gel Electrophoresis).

2. The type of capillary electrophoresis that is most suitable to separate my analyte from other matrix components in my sample is Capillary Gel Electrophoresis (CGE). This is because all other CE techniques separates the components based on charge of the analyte. On the other hand, CGE allows separation to occur based on particle sizes and multiple particle shapes and since my hypothesis require me to test on parameters like particle distribution and particle size, CGE will be a good technique in analyzing my analyte in matrix. It also allows me to do multiple runs in parallel on the same gel with optimized conditions.

3. Suitable conditions of using CGE as a technique:
Buffer composition:0.5x TBE (Tris-borate EDTA buffer)
Buffer pH:~9
Electric field used:150 V
Capillary type: Coating of 100% SH-PEG-COOH

4. I would use a Transmission Electron Microscopy for my detector. It is because electrophoretic mobilities can be quantitatively measure based on the gel mobilities of polymer coated nanoparticles and an image of the interacted electrons transmitted could be obtained to detect this phenomenon.

References:
Separation of Nanoparticles by Gel Electrophoresis According to Size and Shape
Matthias Hanauer, Sebastien Pierrat, Inga Zins, Alexander Lotz, and Carsten Sönnichsen*
Institute for Physical Chemistry, University of Mainz, Jakob-Welder-Weg 11, 55128 Mainz, Germany

Comments

Blog 13. Analaytical Electrochemistry

1. My analyte is electroactive.

2. The hydrolysis of titanium tetra-2-propoxide followed by calicnation at various temperature will recognize Titanium dioxide based on the content and the size of TiO2 strucural form (rutile and anatase). In this paper that I found, there is a correlation in increasing temperature and the structural form of titanium dioxide. The higher temperature, only rutile structure is found in TiO2. This is very useful in analysis of my analyte because my focused analyte is a rutile form of Titanium dioxide.

2.Electrochemistry can help to quantify my analyte. Since my analyte tends to reduce, I can find an electrode that oxidize so that redox reaction can spontaneously take place. From net redox reaction I can obtain my analyte concentration through the Nernst equation and obtain the concentration from the reaction quotient part of the equation and obtain initial concentration of my analyte as an oxidizing agent.


Reference:
Nishimoto S, ohtani B, Hiroshi K and Tsutomu K. Correlation of the Crystal Structure of Titanium Dioxide Prepared from titanium Tetra-2-propoxide with Photocatalytic Activity for Redox Reactions in Aqueous Propan-2-ol an Silver Salt Solutions. J.Cem. Society. 1985. 81. 61-68

Blog 13? - 1pt.

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Blog 9. SDS alone is not a mobile phase (-0.2 pt). In reporting the characteristics of a size exclusion column describe the MW range (or analyte size) (-0.1 pt).

Blog 10. Good answers. If you do decide to use this technique at the end, make sure that you consider that your analyte is particulate when preparing your standards to build calibration curves, preparation procedures, etc.

Blog 11. The selected technique is adequate. However, the explanation why other techniques do not work is not adequate (-.1 pt). What is the electric field used? (-0.1 pt). Also, the explanation why you would use electron microscopy is not adequate either (-0.1 pt)

Blog 10. Problems using Similiar Techniques

1. The preferred technique that I presented to investigate my analytical problem is SSETV-ICP-MS( Slurry Sampling Electrothermal Vaporazation- Inductively Coupled Plasma Mass Spectrometry). Slurry nebulization technique is employed since my analyte will be in solid (powder) form most of the time and by employing this tecnique, time and labor could be reduced in preparing the sample. ICP is coupled with mass spectrometry to separate ions based on the mass-to-charge ratio and the detector could translate the ion signal that is proportional to the concentration. For SSETV-ICP-MS, we are, however, limited with the narrow particle size distribution analysis yet the range of my analyte is within the range. From the paper that I found, this method is found to have a larger tolerance to particle size effect (which is good for my part since I need to analyze my analyte based on different particle sizes) and low detection limits.

2. The other analytical problems that uses similar technique would be:
1 Hedi Nelson's: Exposure to Zinc Oxide and Titanium Dioxide Nanoparticles in Sunscreen
Matrix: Human skin
Analyte type: Nanoparticles of Zinc Oxide and Titanium dioxide
Preferred Technique:ICP-MS

2. Sara Baldvins': Geochemical Mobilization of Arsenic to Ground Water
Matrix: Soil, ground water
Analyte: Arsenic
Preferred Technique: ICP-MS

Blog 9- Chromatographic Techniques

1. Gas chromatography is not suitable for my analyte and its matrix considering that GC only separates low volatile compounds and my analyte has a boiling point above 2000 C. Reverse chromatography is also not a good technique in my case because this technique only separate molecules based on hydrophobic interactions and it is significantly related to the analyte's polarity; Titanium dioxide is an inorganic non-polar compound. The same goes for HILIC, ion exchange, and chiral chromatography where polar analytes will be mostly benefited with these separation techniques. I think size-exclusion chromatography will be the most suitable separation technique to separate my analyte from other matrix components or other impurities existed.
2. Size exclusion chromatography will be the best choice because this technique separates molecules based on sizes. In separating Titanium dioxide from the matrix or impurities presence, this method allows me to further analyze whether particle size play a role in affecting the formulation of a sample of masterbatch production which is a factor that is enlisted in my hypothesis.
3. Commercial column (1)
Nucleogel GFC 1000-8 column (Germany)
Column Lengthx Column Diameter: 300 x 7.7 mm
Particle size: 8 macrometer
Stability condition: pH=10
Temperature=unknown
4. I am not sure about what mobile phase I would use but based on the paper that I have read, SDS (sodium dodecyl sulfate) would be the best mobile phase for this column.
5. The detector that I would most likely use is Slurry Sampling Electro-thermal Vaporization-Inductively Coupled Plasma-Mass Spectrometry (SSETV-ICP-MS) to analyze my analyte based on different particle sizes.
7. Literature Resources:
(1)
Wei G. Shape Separation of Nanometer Gold Particles by Size-Exclusion Chromatography. Analytical Chemistry Society Journal. 1999, 71, 2085-2091
(http://pubs.acs.org/doi/abs/10.1021/ac990044u)

What is being recovered after size exclusion chromatography will be particulate. How will you process these particulate material to make it amenable to mass spectrometry? (-0.5 pt)

Blog 8. Sample Preparation Standard
1. (A)Preparation of slurries
- the titanium dioxide powder with different mean particles is transferred to a flask where 0.01 %(m/v) of polyvinyl alcohol (PVA) as a dispersant and stabilizer to obtain homogenous and stable slurry.
-Disperse the slurries using a ultrasound bath and shake the flask vigorously before starting the analysis.


2.Chromatography for analyte
(1) A sample on analyte with matrix is dissolved in the mobile phase to be homogenized
(2) Inject the mixture in size exclusion colum where the analyte is separated from the matrix and recovered in a storage collector.
(3) The analyte has to be dried up before analysis.
(4)Use mass spectrometry to quantify the concentration of Titanium Dioxide.

Source:
(A)
JOURNAL OF MASS SPECTROMETRY
J. Mass Spectrom. 2006; 41: 1378-1385
Published online 29 September 2006 in Wiley InterScience
(www.interscience.wiley.com) DOI: 10.1002/jms.1111

Blog 6. Good answer.
Blog 7. Line used for AAS? MS spectra? Atomic weight? (-0.2 pt).

Blog 4. In your hypothesis, "important factors" is vague. You need to be more ascertive even if the hypothesis tests negative at the end of the studies.

The first study makes sense, but why aren't you looking at particle size and dispersion? The classification into three categories do not make sense to me.

In the second study, are you also characterizing titanium dioxide contents, dispersion, etc.? If not, how does that test your hypothesis.

The relevance of the third study is unclear to me. (-0.5 pt).

Blog 5. The first answer is ok. However, you are saying that fluorescence is not suitable for your analyte. Why do you suggest to use x-ray fluroescence?

Blog 5. Fluorescence Techniques(Revized)

4. Since my analyte, Titanium Dioxide, is not fluorescent and I am not sure whether complexation, derivation and quenching would affect the optical and the mechanical properties of my analyte and matrix or these approaches may lead to degradation of my analyte.In order to study my analyte, I have to using Infrared (IR) spectroscopy instead. Titanium dioxide is used in two crystal forms namely anatase and rutile. In masterbatch industry,rutile form is chosen for Titanium Dioxide. The IR of this material shows that it has peaks at 610 and 446 cm-1 with the broad peak between 800 and 470 cm-1.

Source:

Jackson, K.D.O. A Guide to Identifying Common Inorganic Fillers and Activators Using Vibrational Spectroscopy. Journal of Vibrational Spectroscopy [Online]. Volume 2 Edition 3 http://www.ijvs.com/volume2/edition3/section3.html (accessed Oct 18, 2011)

5. X-ray fluorescence spectrometry is the type of instrument that is mostly suited for my sample and analysis. This is because this instruments allows measurements to be done in solid state which is very applicable to my case, it has a high precision of analytical measurements in determining major elements. Also, this instrument could detect as few as several thousand atoms using x-rays to excite element and to create a quantitative and qualitative map for my samples. In observing my analayte as nano particles, this technique possesses a series of analytical characteristics that are valuable (in some senses) for routine analysis too.

Source:

Potts, P.J and Webb.P.C. X-ray Fluorescence Spectrometry [Online]. In: G.E.M Hall (Editor). Geoananalysis. J. Geochem. Explor., 44:251-296

Blog 5. Fluorescence Techniques

4. Since my analyte, Titanium Dioxide, is not fluorescent and I am not sure whether complexation, derivation and quenching would affect the optical and the mechanical properties of my analyte and matrix or these approaches may lead to degradation of my analyte.In order to study my analyte, I have to using Infrared (IR) spectroscopy instead. Titanium dioxide is used in two crystal forms namely anatase and rutile. In masterbatch industry,rutile form is chosen for Titanium Dioxide. The IR of this material shows that it has peaks at 610 and 446 cm-1 with the broad peak between 800 and 470 cm-1.

Sources:
Jackson, K.D.O. A Guide to Identifying Common Inorganic Fillers and Activators Using Vibrational Spectroscopy. Journal of Vibrational Spectroscopy [Online]. Volume 2 Edition 3 http://www.ijvs.com/volume2/edition3/section3.html (accessed Oct 18, 2011)

5. X-ray fluorescence spectrometry is the type of instrument that is mostly suited for my sample and analysis. This is because this instruments allows measurements to be done in solid state which is very applicable to my case, it has a high precision of analytical measurements in determining major elements. Also, this instrument could detect as few as several thousand atoms using x-rays to excite element and to create a quantitative and qualitative map for my samples. In observing my analayte as nano particles, this technique possesses a series of analytical characteristics that are valuable (in some senses) for routine analysis too.

BLOG 4-Studies needed to investigate my analytical problem

I think I would like to use this opportunity to update my hypothesis:
Titanium dioxide's actual content that correlates closely with its particle distribution and size are important factors in determining the optical properties (dispersibility, opacity) and the homogeneity in mixing as well as an ability for other components in masterbatch (especially pigments) to perform optimized coloration and pigmentation.

Studies:
1) Determine the standard for the "problematic" masterbatch productions (production that always deal with reformulation-QC lab reinvent new formulation for every production that consumes more time and resources) to do tests to obtain the actual content of TiO2 for each production, the opacity, dispersibility. Separate the standards based on these 3 categories: polymer resin used(PVC, PC, PE), colors of final product(dark, white, mixed colors) and source/ suppliers.

2)Identify a group of productions that are "problematic" and identify the differences and similarities of the optical properties with the standard obtained in studies no 1).

3) Identify the characteristics of different types of process of manufacturing masterbatch and different possibilities for same masterbatch production manufactured using different process.

Estimate of analyte level in the matrix:
According to many research papers that I have reviewed, the amount of analyte level is dependent on what kind of output I want to obtain (higher elongation, tensile strength, energy efficiency, different gradibility, etc). However, since I focus more on the optical properties of my analyte in the matrix of polymer resin, from one of the sources I have read, the estimate level of analyte has to be around 0.5% to 5% by weight in order for better dispersion and better opacity to be achieved so formulation is avoidable.

Sources:
R.E.Day. The Role of Titanium Dioxide Pigments in the Degradation and Stabilization of Polymers in the Plastic Industry. Science Direct, UK. 2003.Page 73-92.Doi:10.1016/0141-3910(90)90023-Z
(http://www.sciencedirect.com/science/article/pii/014139109090023Z)

BLOG 3. Parts (a) and (b) are fine. Part (c) is not quite right. You need to talk about studies that are different not methods. (-0.25 pt)

Prof. Arriaga, I would just want to remind you that I have updated and modified my entry as what we have talked about on Wednesday. Thank you.Revy

Revy,
see instructions for BLOG 3. You need to modify your entry. If you do not know how to do it, consult with Chad. Once you have modified your entry your grade will be released. Please notify Chad when this is done. Thanks. Edgar
Regarding your answers....

- (a) Good choice. You are not answering parts (b) and (c). (-0.5 pt).

I think one analytical problem that is similar to mine would be Heidi Nelson's analytical problem of "Exposure to Zinc Oxide and Titanium Dioxide Nanoparticles in Sunscreen". Other than the fact that we both focus on similiar analyte, I think my analytical problem mainly focus on particle size of the analyte and the optical properties that it has such as scattering of light, dispersion, etc. This property narrows down our choices of method in sample calculation and analysis. Since the optical properties relate closely with a particle size and distribution, it is important to separate these nanoparticles by size and then measure the concentration according to the signal response making use of calibration curves. With these measurements, multiple sampling will help me to calculate and analyze the particle size distribution and how the content of TiO2 as my analyte in deviating other pigments and additives to mix homogenously and reproduce similar masterbatch production with both standard or previous masterbatch production.

I do not understand the relevance of the second paragraph to the problem that you are describing in the first paragraph. (-0.1 pt).
What is your hypothesis? (-0.2 pt)

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